President Trump’s 2019 budget request proposes investing $617 billion in the Defense Department. It’s a significant increase, one that will allow the Pentagon to begin rebuilding our depleted and sorely stressed military. On the campaign, candidate Trump pledged to strengthen every branch of our military, but once in the Oval Office, his first-year defense budget request was underwhelming. To a large extent, it reflected a continuation of Obama-era military priorities, with a few changes at the margins.

This is what led Congress to move first. It was Congress that pushed and got an increase in the defense budget. Even before there was an official White House budget request, Sen. John McCain (R-Ariz.) and Rep. Mac Thornberry (R-Texas) put forward defense budget requests that focused on what it would take to make our military whole again.

For 2019, it appears Defense Secretary James Mattis was able to craft a budget that will put the nation’s military on track for a substantive rebuild. It represents an acknowledgement by the Trump administration that the military requires substantial resources in order to regain its lost readiness. This request puts the president’s budget back in the driver’s seat of the defense budget conversation.

The budget outlines a goal to phase out war spending and move those resources to a more stable footing. If Congress accomplishes this, it will have taken a big step toward creating a more sustainable defense budget. The president’s budget calls for an increase of 16,900 troops over the current level authorized by Congress. It is a more modest increase than the 25,600 increase recommended by my colleagues at the Heritage Foundation, but it is great sign that the department seeks to move away from the era of having to do more with less people.

However, the budget fails to advance some of the cost-saving measures that would be more than welcome in an era of trillion-dollar deficits. For example, it fails to request a new round of base realignment and closure, something that would likely save the Defense Department $2 billion each year and could actually help improve readiness in the bargain.

Yes, the base realignment and closure process needs to be reformed. But Congress and the Pentagon need to start that discussion now. Punting the request to a future year will not accomplish the necessary changes. Overall, the president’s budget proposal should be measured against the criteria and the priorities established in the administration’s National Defense Strategy, released in January. The strategy described the need for a defense budget that is sustained, predictable and increased.

Of course, producing a sustainable, predictable defense budget requires congressional action. The Budget Control Act set spending limits, which were subsequently raised through four different budget deals. For the last seven years, these caps have been at the center of all federal budget discussions. It will be no different in the future. After all, while the budget deal last week raised the fiscal 2019 cap on defense spending to $647 billion, the caps for fiscal 2020 and 2021 are still in place, at $576 billion and $590 billion, respectively.

Since 2011, the Budget Control Act caps have limited the amount of resources our nation can dedicate to its defense. Worse, they have taken a far larger toll on the military than they have on domestic spending. Unless Congress jettisons these artificial limitations on defense spending — limitations which fly in the face of increasing real-world demands on our armed forces — it will be virtually impossible to provide the sustainable, predictable funding needed to rebuild our military and support the National Defense Strategy.

Overall, the president’s second defense budget more closely aligns with what congressional leaders such as McCain and Thornberry have long seen as necessary. All signs indicate that the bigger, better defense budget will find the sailing smoother as it works its way through the often turbulent waters of Capitol Hill. But absent reform of the Budget Control Act, the prospects for the Pentagon getting the sustained, predictable funding it needs to overcome years of underinvestment are very dim indeed.